Hi all, I recently started a new vivarium build and I've run into a bit of an issue. I've used the expanding foam sparingly before to create a few ledges and it's worked well, but this is my first time trying to do a full foam background, so I'm hoping someone with some more experience using the foam can give me some insight. Anyway, I applied the foam a few days ago and left the terrarium laying on it's back while it dried. I had purposely put it on a little thick in some areas with the idea that I could carve it back to exactly where I wanted it. However, when I tipped it back up this morning I noticed that while the outside has dried hard, one of the thicker areas has a spot against the back glass that has not dried, but instead looks like the stuff has kind of separated out and there is a bubble of liquid resin trapped there. So, has anyone experienced this before? I have two theories: One is that I just put it on too thick and the outside layer cured before the inside could dry properly. Two is that the can of foam I used was about 11 months past it's "best before" date (I didn't notice this until it was too late), and the age has degraded it's performance. And of course there is always the possibility that it is a combination of the two factors. Does anyone have any other ideas what might cause this? So now I'm wondering what my options are. Do you think it will dry eventually if I leave it long enough? Or am I going to have to cut that area out and redo it? I'm also considering trying to drill a few holes through the hardened part into the bubble area to get some air in there to help it dry. Any insight would be much appreciated!